Denny Schrock

signs of spring

I heard them yesterday on my lunch-hour run near the Raccoon River. The spring peepers (Pseudacris crucifer) were chirping in full chorus. These tiny little frogs are one of the sure signs of spring. The males create a cacaphony of music in their attempt to attract mates who will lay their eggs in small ponds that often dry up later in the year.

Yellow crocus (Crocus flavus)

Yellow crocus (Crocus flavus)

Those spring peepers made me think of other signs of spring that I noted in my yard this week, and wondered whether they could be consistently connected. These cheery yellow crocus came into full bloom in my backyard, where they fill two quadrants of a boxwood parterre. Other crocuses also have come into full glory this past week. Pale blue ‘Blue Pearl’, deep purple ‘Grand Maitre’, and creamy ‘Romance’ snow crocus brighten the garden beds.

I also noticed some of the early irises blooming. This bright yellow danford iris (Iris danfordiae) greets me as I walk to the mailbox. Deep blue ‘Harmony’ reticulate iris (Iris reticulata) and purple ‘George’ Spanish iris (Iris histrioides) popped through the winter mulch this week, too.

Danford iris (Iris danfodiae)

Danford iris (Iris danfordiae)

Could these early-season crocuses and irises be indicators of the awakening of spring peepers? I’ve not necessarily made the connection before. Phenology, the correlation of biological phenomena with climatic conditions, can be used by gardeners to watch for or treat certain pests. For example, recommendations to apply crabgrass preventer when forsythias are in bloom stem from the need to get the weed preventer in place before the ground warms to 55 degrees F, the temperature at which crabgrass seeds begin to germinate.

Have you made connections between bloom dates in your yard with other natural phenomena? If so, we’d love to hear about them.